Dynamena quadridentata
The annular corrugations on the gonothecae are usually not all the same depth around the body, tending to become shallower on one side.
The annular corrugations on the gonothecae are usually not all the same depth around the body, tending to become shallower on one side.
Stems simple, straight, to 10 mm high, arising from a tubular, reptant hydrorhiza. Proximal stem region tubular, athecate, perisarc thick, ending in a strong hinge joint; stem thereafter thecate, internodes with three or four pairs of opposite hydrothecae, nodes transverse, collar-shaped, a short infrathecal part below hydrothecal groups.
Hydrothecae frontal on stem, laterally separated or sometimes in contact; hydrotheca almost tubiform, 15 maximum width in distal third, bases and adcauline walls in contact in each internodal group, adnate adcauline wall convex, free part short, concave to convex, abcauline wall concave to margin, a submarginal knob of perisarc below margin; base of hydrotheca flat to slightly concave, a small knot of perisarc at base of adcauline wall. Margin facing outwards, oval, with two almost triangular lateral lobes and a minute adcauline cusp, perisarc thin, an abcauline opercular flap attached to submarginal knob.
Hydranth with about 16 tentacles on a short, wrinkled column, no caecum.
Gonotheca large, arising from hydrorhiza on a moderately long cylindrical pedicel; barrel-shaped, widest about middle; body with 6–8 deep annular corrugations, apex transverse, truncate, with thickened rim. Gonophore slender, cigar-shaped containing numerous small ova.
Colour honey-brown.
Hebella scandens (Bale, 1888) is a common epizoite of the colonies.
Circumglobal in tropical and subtropical waters.
Subtidal, epizoic on other hydroids.